Deflection Properties Research Articles

The effect of different clinical recycling methods on load deflection properties of super-elastic and thermal nickel-titanium orthodontic arch wires: A comparative assessment.

Repeated clinical use of arch wires requires sterilization and may result in alteration of the properties of the wires as they get subjected to corrosion and cold working. Therefore, the present study aimed to assess the effects of different clinical recycling methods on the load-deflection properties of super-elastic and thermal nickel-titanium orthodontic arch wires. A total of 50 0.014" round nickel-titanium orthodontic wires [Group I: super-elastic nickel-titanium (n = 25) and Group II: thermal nickel-titanium wires (n = 25)] were tested for changes in their load deflection properties after three different recycling methods, that is, dry heat sterilization, autoclave, and cold sterilization. For each group, five wires as received from the manufacturer were taken as control (T0), and the rest of the 20 wires were placed intra-orally for a duration of one cycle of clinical use (T1). Five wires out of these were subjected to 3-point bending tests, and the rest of the wires were subjected to different recycling methods. Load deflection properties of recycled wires were measured with an Instron universal testing machine. The results were tabulated, and the data were analyzed by analysis of variance (ANOVA) with the Tukey post hoc test. Statistically, no significant difference was found in the super-elastic group between samples recycled by dry heat, autoclave, and cold sterilization when compared with as-received super-elastic NiTi up to 2.5 mm of deflection. A highly significant difference was found between as-received thermal NiTi group (83.51 ± 6.49 N/mm) and samples recycled by dry heat (53.73 ± 4.72 N/mm), autoclave (45.38 ± 4.37 N/mm), and cold sterilization (48.44 ± 3.12 N/mm) at 0.5 mm of deflection. Among thermal NiTi, any of the sterilization methods could opt at all deflections. For super-elastic NiTi, at higher deflections or in cases of crowding of more than 2.5 mm, cold sterilization should be the method of choice, whereas any sterilization method can be used at deflections less than 2.5 mm.

Cu-doped KTN crystal with controllable, reversible, and fast photochromic properties: A superior electro-optical material for improving beam deflection performance

Improving the deflection performance of a beam deflector is urgently required to acquire optical signals for space laser communication and change the attitude and position of space targets and spacecraft. In this work, a Cu-doped potassium tantalate niobate (Cu-KTN) single crystal with fast photochromic and increased beam deflection properties is synthesized using the top-seeded solution growth method. When a Cu-KTN single crystal is irradiated with 405 nm light or ultraviolet (UV) light, the color changes from pale green to reddish brown. After light irradiation, the color gradually returns to yellowish green. Decolorization is accelerated under irradiation with green light or long-wavelength light, and the color changes to pale green. The origin of reversible photochromism reveals the fast valence change of Cu ions. In addition, ion doping improves the beam deflection angle of the secondary electro-optical effect of Cu-KTN (4.3 mrad, 1000 V) crystal compared with pure KTN (3.2 mrad, 1000 V). This study successfully synthesizes Cu-KTN single crystals with photochromic uses and establishes a new route for beam deflectors with significant deflection angles.

Measurement of space charge density distributions and dielectric resonance enhancement of beam deflection properties of KTN crystal

In recent years, potassium tantalum niobate (KTN) electro-optical deflection devices have gained considerable attention because of their notable advantages, such as large deflection angles, low operational voltage requirements, and compact dimensions. This study uses the phase-shifted interferometric optical path to characterize the influence of direct current (DC) voltage on charge density. An interferogram is acquired using the four-step phase-shifting technique, enabling the calculation of phase delays and deducing the variation in charge density. Experimental results demonstrate that the charge density near the cathode increases with an increase in DC voltage. Subsequently, we utilize the frequency dependence of the dielectric constant of the KTN crystal on the electric field. The dielectric constant can be enhanced when the characteristic frequency of the motion of the polar nanoscale region matches the frequency of the electric field. This field-induced enhancement effect improves the beam deflection performance of the KTN crystal. Application requirements in the field of high-speed random scanning can be realized through the mechanism of the KTN crystal co-acting with DC and alternating current electric fields.

Mix Design and Field Detection of Large-Particle-Size Graded Crushed Stone Mixtures for Pavement Reconstruction

Large-particle-size graded crushed stone mixtures (LPS-GCSMs) can improve the shortcomings of conventional graded crushed stone, such as low strength, high deformation, and a low modulus of resilience. At present, there is no systematic research on the gradation design and field evaluation of the LPS-GCSMs. In this study, compaction and California bearing ratio (CBR) tests and field construction conditions were combined to design six kinds of gradation of LPS-GCSM, and the optimum gradation was revealed. In order to improve the mechanical properties of LPS-GCSM, 2.5% cement was added to the mixture to prepare a low-content cement-modified LPS-GCSM (LCC-LPS-GCSM) based on the suggested gradation. The mechanical properties of the LCC-LPS-GCSM were investigated through unconfined compression strength (UCS) and compression rebound modulus (CRM) tests. Moreover, the compaction and deflection properties of LPS-GCSM and LCC-LPS-GCSM were examined through the test battery. The results showed that the optimum gradation of LPS-GCSM can be achieved with a combination of aggregate sizes of 20–40 mm, 10–20 mm, 5–10 mm, and 0–5 mm at a ratio of 44:20:10:26. The passing rates of 19 mm and 4.75 mm should be approximately at the median value of the gradation in view of field construction uniformity and a coarse aggregate interlocking effect. The UCS and CRM values of LCC-LPS-GCSM increased rapidly from 0 day to 28 days while they slowed after 28 days, which was similar to those of cement-stabilized materials. The field detection suggested that LPS-GCSM exhibited favorable compaction and that the addition of cement improved the stability of the field compaction of the mixture. Adding a subbase course of LPS-GCSM between the old pavement and the LCC-LPS-GCSM base can lead to more uniform stress on the base. The results of this study provide a reference for the gradation design of LPS-GCSM and optimization of the design indicators.

Performance of doubly reinforced concrete beams with GFRP bars

Abstract The study focused on examining the behavior of six concrete beams that were reinforced with glass fiber-reinforced polymer (GFRP) bars to evaluate their performance in terms of their load-carrying capacity, deflection, and other mechanical properties. The experimental investigation would provide insights into the feasibility and effectiveness of GFRP bars as an alternative to traditional reinforcement materials like steel bars in concrete structures. The GFRP bars were used in both the longitudinal and transverse directions. Each beam in the study shared the following specifications: an overall length of 2,400 mm, a clear span of 2,100 mm, and a rectangular cross-section measuring 300 mm in width and 250 mm in depth. To apply loads for testing, two-point static loads were placed at the middle third of the beam’s span, creating a shear span of 700 mm in length. The beams were categorized into three groups depending on the GFRP longitudinal reinforcement ratio in the tension and compression zones of the section. GFRP bars with a diameter of 15 mm were employed as longitudinal reinforcement, while closed GFRP stirrups with a diameter of 8 mm at 100 mm were utilized as transverse reinforcement throughout the structural element. Test results have indicated that the ultimate load capacity of doubly GFRP-reinforced concrete beams varies compared to singly GFRP-reinforced beams. The range of variation observed is between an increase of 8% and a decrease of 4%. Accordingly, the contribution of the GFRP bars in the compression zone is insignificant and could be ignored in design calculations. It was observed that the loading level at which crack spacing stabilized ranged between 31.3 and 87% of the experimental failure load. It seems that the crack spacing decreased with the increase in the reinforcement ratio.

Metasubstrate-based SH guided wave piezoelectric transducer for unidirectional beam deflection without time delay

Focusing the energy of a guided wave along a desired direction is of great significance in structural health monitoring (SHM), since it can improve the sensitivity to defects and reduce the complexity of signal interpretations. The phased array method is the most common approach for beam deflection, which requires a high uniformity of each element and the support of expensive and complex electronics. Moreover, the mirrored wave beam cannot be avoided for a linear array, resulting in the difficulty of distinguishing the defects at the symmetric positions. In this work, a metasubstrate-based piezoelectric transducer (MSBPT) is developed for unidirectional SH0 wave (the fundamental shear horizontal wave) beam deflection under a single driving source. The proposed MSBPT is constituted by a metasubstrate and two columns of thickness-shear mode PZT wafers. The metasubstrate is designed to provide the required phase gradient for unidirectional beam deflection, so no extra time delay is needed during excitation and reception. An analytical model is proposed to guide the design of the transducer to obtain the desired wave beam. The beam deflection properties of the MSBPT are validated by finite element simulations and experiments. It is observed that the MSBPT can concentrate the energy of the generated SH0 mode only in one desired direction with a small divergence angle. Moreover, the MSBPT can also serve as a sensor that only receives the SH0 mode propagating from the deflection angle and filters out the wave energies from other incident angles. Due to the simple configuration, the proposed MSBPT will be helpful in the controllable generation and reception of SH0 mode in SHM.

Flexural Strengthening of Concrete Structures Using Externally Bonded and Unbonded Prestressed CFRP Laminates: A Literature Review

Carbon fiber-reinforced polymer (CFRP) materials have been widely used in prestressed and non-prestressed systems for the flexural strengthening of concrete structures in many construction projects worldwide. Strengthening with non-prestressed CFRP materials, which is known as passive repair, could lead to an increase in the ultimate capacity of the concrete member. However, it has little effect on its serviceability performance (e.g., cracking, yielding, and deflection properties). Flexural strengthening with prestressed CFRPs provides an active repair technique that positively effects the strength and serviceability of structures. In addition, strengthening with prestressed fiber-reinforced composites efficiently uses the material’s high tensile strength. Although different fiber-reinforced polymer (FRP) materials and forms have been used in prestressing applications, this paper focused on the use of CFRP laminates (e.g., sheets, strips, or plates). These laminates have been widely used due to their excellent mechanical properties, ease of application in various geometrical shapes, good conforming surface area of contact with structures, and low installation costs. A comprehensive literature review was presented on strengthening using prestressed CFRP laminates in conventionally and internally prestressed concrete structures (PCSs). The externally bonded and unbonded prestressed CFRP laminate applications that used different anchorage systems were presented. The flexural behavior, failure modes, and serviceability performance of the strengthened concrete members were discussed. The effects of the prestressing level on ductility and energy absorption and a summary of the recommended optimum prestressing level discussions were presented in this paper. Furthermore, a review of the theoretical studies that were conducted for prestressed CFRP applications was provided. The knowledge gaps in the research area and future research recommendations were presented.

Performances of green velvet material (PLON) used in upholstered furniture

Green Velvet Material (PLON), which is prepared from polyester slices, has been called a green material based on its ester composition, its ability to be degraded, and the possibility of recovering the value of used material by reprocessing. PLON is expected to be used as a material for the padding layer of upholstered furniture. This paper presented a comparative study of traditional flexible polyurethane foam and Green Velvet Material as the upholstered furniture’s padding layer. The compression mechanical properties of Green Velvet Material and flexible polyurethane foam, such as indentation force deflection, support performance, compression set, and resilience property, were analyzed. The results showed that Green Velvet Material had lower surface hardness and higher comfort compared to flexible polyurethane foam. In terms of resilience, both high-density and low-density Green Velvet Material performed better than the foam control group, but Green Velvet Material had a poorer ability to regain its shape after prolonged pressure. The 30 kg/m3 density Green Velvet Material was the closest to the compression and resilience properties of flexible polyurethane foam. The conclusions provide theoretical data for the effective and reasonable application of Green Velvet Material in upholstered furniture.

Research on Structural Performance of Hybrid Ferro Fiber Reinforced Concrete Slabs.

Reinforced concrete structures, particularly in cold areas, experience early deterioration due to steel corrosion. Fiber-Reinforced Concrete (FRC) is an emerging construction material and cost-effective substitute for conventional concrete to enhance the durability and resistance against crack development. This article examines the structural performance of hybrid ferro fiber reinforced concrete slabs (mix ratio of mortar 1:2) comprising silica fume, layers of spot-welded mesh and different ratios of polypropylene fibers. The ferrocement slabs are compared with a conventional Reinforced Cement Concrete (RCC) slab (mix ratio of 1:2:4). The experimental work comprised a total of 13 one-way slabs, one control specimen and three groups of ferrocement slabs divided based on different percentages of Poly Propylene Fibers (PPF) corresponding to 0.10%, 0.30% and 0.50% dosage in each group. Furthermore, in each group, the percentage of steel ratio in ferrocement slabs varied between 25% and 100% of the steel area in the reinforced concrete control slab specimen. For evaluating the structural performance, the observation of deflection, stress-strain behavior, cracking load and energy absorption are critical parameters assessed using LVDTs and strain gauges. At the same time, the slabs were tested in flexure mode with third point loading. The experimental results showed that the first cracking load and ultimate deflection for fibrous specimens with 0.5% fiber and 10% silica fume increased by 15.25% and 13.2% compared with the reference RCC control slab. Therefore, by increasing the percentage of PPF and steel wire mesh reinforcement in the ferrocement slab, the post-cracking behavior in terms of deflection properties and energy absorption capacity was substantially enhanced compared to the RCC control slab.

Influence of morphology and architecture on properties and applications of MXene polymeric nanocomposites

Morphological characterization of fabricated MXene (M-X) Polymeric nanocomposites (M-X@PNC) is critically imperative for in depth appraisal of surface-topographical and compositional evaluation of M-X@PNC. The garnered properties of M-X@PNC are function of the degree of nanoparticulate distribution and embedment within the polymeric matrices and their overall effectiveness at improving the nanocomposites properties, vis-a-viz mechanical, heat dissipation as well as heat deflection properties along with potential applications. Inherently interacting functional entities within M-X@PNC architecture are basis for garnered properties including flammability, chemical, thermal, electrical conductivity and so on, which directly affect potential applications. Thus, this paper elucidates the influence of morphology and architecture on M-X@polymeric nanoarchitectures properties and applications.

Nonlinear modeling and experimental characterization of hydraulically interconnected suspension with shim pack and gas-oil emulsion

Although hydraulically interconnected suspension (HIS) have been regarded as one of the promising suspension architectures in recent years, it’s application is still limited due to the many simplifying assumptions in the modeling and analyzing. There has been no published detailed analysis of the effects of shim pack deflection and entrapped gas within oil in HIS system to date. In this study, a nonlinear physical model of HIS is presented with an emphasis on the shim pack deflection and gas-oil emulsion properties and their effects on the stiffness and damping performances. The deflection of the shim pack is formulated based on shim pack deflection theory, and a nonlinear correction function (NCF) is proposed to compensate the errors of the analytical model. The finite element analysis (FEA) method is adopted for parameter identification. Also, the formulation of gas-oil emulsion is derived, in which the variations in the mass density and bulk modulus of the emulsion are formulated as a function of the gas volume fraction. The bench tests for the stiffness and damping characteristics are carried out to validate the developed physical model using the measured strut forces. The measured data and the model are analyzed to highlight the effects of gas-oil emulsion on the stiffness and damping characteristics. Furthermore, the effects of the initial gas volume fraction within oil is discussed under different motion-mode excitation. The results show that the entrapped gas volume changes the compressibility of the emulsion and thus cause significantly reduction to damping forces in a highly nonlinear manner but approximately linear increase to spring forces. It also suggests that the gas volume fraction should be controlled within 4%, so as to reduce the unexpected elastic force caused by gas compression.

Multifunctional blazed gratings for multiband spatial filtering, retroreflection, splitting, and demultiplexing based on C2 symmetric photonic crystals

The concept of multifunctional reflection-mode gratings that are based on rod-type photonic crystals (PhCs) with C2 symmetry is introduced. The specific modal properties lead to the vanishing dependence of the first-negative-order maximum on the angle of incidence and the nearly sinusoidal redistribution of the incident-wave energy between zero order (specular reflection) and first negative diffraction order (deflection) at frequency variation. These features are key enablers of diverse functionalities and the merging of different functionalities into one structure. The elementary functionalities, of which multifunctional scenarios can be designed, include but are not restricted to multiband spatial filtering, multiband splitting, retroreflection, and demultiplexing. The proposed structures are capable of multifunctional operation in the case of a single polychromatic incident wave or multiple mono-/polychromatic waves incident at different angles. The generalized demultiplexing is possible in the case of several polychromatic waves. The aforementioned deflection properties yield merging demultiplexing with splitting in one functionality. In turn, it may contribute to more complex multifunctional scenarios. Finally, the proposed PhC gratings are studied in transmissive configuration, in which they show some unusual properties.

A spatial distribution effect of almond shell bio filler on physical, mechanical, thermal deflection and water absorption properties of vinyl ester polymer composite

AbstractThe present work deals with the effective utilization of almond shell bio‐waste fillers in the production of vinyl ester polymer composites. The almond shell particle surface was chemically modified by alkaline treatment. The almond shell particles with varying weight percentages of 5%–30% were used to prepare the vinyl ester polymer composite. The experimental results show that a 25% addition of alkaline‐treated almond shell particles significantly improved the mechanical properties of the composite when compared to pure vinyl ester and untreated almond‐filled composite samples. The highest tensile, flexural, impact strength, and Shore D hardness of the 25% alkaline‐treated almond shell composite were 54, 142 MPa, 31, and 79 kJ/m2, respectively. This was due to the alkaline treatment of almond shell particles, which improved the interfacial adhesion between the vinyl ester matrix and almond particles. The heat deflection temperature of the 25% alkaline treated almond shell particle‐filled vinyl ester matrix composite was 72°C. The thermal insulating characteristics of alkali‐treated almond shells were improved due to the reduction of quickly thermal degradable materials such as hemicelluloses and lignin, as indicated by Fourier transform infrared spectroscopic data, and more exposure of minerals to the surface, as confirmed by energy dispersive X‐ray analysis. The addition of alkaline‐treated almond shell particles improves the characteristics of the vinyl ester matrix and allows the development of biocomposites.

Impact Properties of Novel Natural Fibre Metal Laminated Composite Materials

Fibre metal laminates (FMLs) are lightweight structures with high structural performance and are suitable for many industrial applications. This work describes the impact behaviour of novel sisal fibre-reinforced aluminium laminates (SiRAL) and their dependence upon the orientations of the fibres, the composite core used and the surface treatment of the metal skins. A cold-pressing technique is used to produce SiRALs in six configurations. The FMLs here also have treated or untreated aluminium skins (2024 T3) and three different types of core materials (0°/90° fabric, ±45° fabric and random matt). The ±45° core treated SiRAL provides the highest energy absorption and deflection properties. The pre-treatment of aluminium skins using sandpaper, deep cleaning and primer significantly affects the delamination of the panels under bending impact. The findings reveal that the SiRAL concept is a promising multifunctional FML suitable for different applications that require lightweight, bending and impact performance, together with sustainability characteristics.

Load deflection behaviour and properties of sustainable lightweight aggregate concrete slabs

This research has been conducted to investigate the effect of partial replacement of coarse aggregate by lightweight aggregate on different characteristics and load deflection behaviour of concrete. Natural aggregate was replaced once by waste walnut shell and then by porcelinate aggregate. And both types are considered lightweight aggregate. Percentages of replacement by volumetric rates ranging between 25% to 100% were adopted. In addition, cement was replaced by 10% waste glass powder. Compressive strength, splitting tensile strength, and dry density were made. Also, one-way slab was cast for 50% replacement and tested under four point flexural test. Results showed that replacement of natural aggregate with lightweight aggregate regardless of its source decrease density, compressive strength and splitting strength. While an increase in the deflection at failure was noticed for slabs incorporating lightweight aggregate compared to the reference one. Concrete containing 50% porcelinate demonstrated a slight increase in strength compared with the reference slab by 8.91% concrete containing 50% WA demonstrated a clear reduction in strength compared with the reference slab by 62.57%. The width of crack at failure for concrete incorporating walnut coarse aggregate was wider for the reference one. While concrete incorporating porcelinate failed with finer cracks than the reference one.

Load deflection behaviour and properties of sustainable lightweight aggregate concrete slabs

Load deflection behaviour and properties of sustainable lightweight aggregate concrete slabs

Load Deflection Properties of Small Diameter Titanium-Niobium-Tantalum-Zirconium Archwire(An In Vitro Study)

Objectives: This study aimed to evaluate the load deflection properties of new niobium-based beta titanium archwire (Gummetal) in comparison with superelasticnickel titanium (SE-NiTi) and copper NiTinickel titanium (Cu-NiTi) archwires. Methods and Material: Gummetal, superelasticNiTiand copper NiTiarchwire segments of 0.014-inch diameter were examined by three point bending test, using Instron testing machine with 10 Newton (N) load cell. Wire segments were tested at 2 and 4 mmdeflections, and at a temperature of 37±1ᵒC. Oneway analysis of variancewas used to compare the means of the groups at a significance of p ˂ 0.05.Results: At 2 mm deflection, the maximum force values and unloading forces of Gummetalwere significantly higher than those of the control (SE-NiTi and Cu-NiTi) archwires. At 4 mm deflection, there was no significant difference between the maximum force values of Gummetal and SENiTiarchwires, however they were significantly higher than those of Cu-NiTiarchwire. Unloading forces of Gummetalarchwire at 4 mmdeflection were initially significantly higher, then became significantly lower than the control wires at 1 mm unloading deflection point.Conclusions: The present study showed that Gummetalarchwirewas less efficient in providing continuous forcesin comparison with SE-NiTi and Cu-NiTiarchwires.Gummetalarchwire cannot be considered superelastic, and its use in the alignment phase may better be limited to mild crowding cases.

Modeling thermo‐mechanical behaviors of carbon nanotube/polyurethane functionally graded shape memory polymer beam

AbstractIn this paper, a new constitutive model which can model the thermo‐mechanical behaviors of functionally graded shape memory polymer (SMP) beam is established. The kinematic equation was established based on the SMP constitutive equation further derived and Euler–Bernoulli beam theory. The material parameter equations were established by taking the volume fraction of carbon nanotubes (CNT) as the gradient based on the material parameter equations of SMP and properties of functionally graded materials. According to the constitutive model, the simply supported beam was taken for example to be solved and simulated by using the virtual work principle. The results show material parameters properties, deflection properties, stress properties and shape memory properties of CNT/carbon nanotube/polyurethane (PU) functionally graded beam and some conclusions are concluded. This work shows the thermo‐mechanical behavior of CNT/PU functionally graded beam, and it provides a theoretical basis for the practical application of functionally graded SMP materials.

Microcantilever geometry analysis for array sensor design

In terms of fabrication and functioning, cantilevers are the simplest Micro Electro Mechanical Systems(MEMS) based devices. These cantilever based sensors have gradually progressed in all domain applications and may now found virtually everywhere. The usage of these MEMs based sensors is increasing gradually because of the distinct benefits that they provide. In high sensitivity applications like molecular sensing, microcantilever based sensors offer great promise for detecting a wide range of target atoms in gaseous and fluid medium as well chemical, and biological sensing applications. They too have an extensive range of applications in medicine, especially for early detection of more life-threatening diseases, identify intermolecular gene mutations, monitoring blood sugar levels, and detecting chemical and biological warfare agents. These cantilever based sensors offer numerous benefits over conventional diagnostic methods, including sensitivity, economical, easy to use, low analyte needed (in µl), non-hazardous procedures, and rapid response. In this study, we will explore the characteristics of two types of cantilever beams by modifying five types of materials, namely silicon, silicon dioxide and polysilicon, silicon nitride, and silicon carbide. Deflection properties are analysed by conducting a parametric sweep on arc length in order to build an array sensor. According to the simulation results the eigenfrequencies of the proposed array for the subjective load of 1Kda, 2Kda, 3Kda, 4Kda are 44×106,38×106,29×106,19×106respectively.

Design and Analysis of Foldable Vehicle using Finite Element Simulation

Present work deals with evaluation of stress, deflection and dynamic properties of the folded vehicle structure. The folded vehicle in present case is a single seat vehicle intended to carry one person. Design constraints are the folded dimensions of the vehicle and the maximum vehicle speed is limited to 15m/s. Using classical calculations dimensions of the vehicle are devised. Different materials are used for seat, telescopic support and chassis of the foldable vehicle. computer aided model is prepared using CATIA software. Finite element analysis of the foldable vehicle has been carried out to evaluate the static and dynamic stresses induced in the vehicle components. Meshing of the foldable vehicle is carried using Ansys Workbench. From modal analysis six mode shapes of the foldable vehicle are formulated, corresponding frequencies and deflections are devised. Mesh generator is used to mesh the foldable vehicle. The deflection and frequency magnitudes of foldable vehicle evaluated are in good agreement with the experimental results available in literature for similar materials.